Cooking temperature

Hi Everyone. I am cooking a round loaf in a dutch oven using a recipe from the book "Flour Water Salt Yeast." The recipe is 500g white flour and 72% hydration. I am using a white 4.5 quart Le Creuset round dutch oven to cook it in. The book calls for baking the loaf at 475 degrees for 30 minutes with the top on, and 20 minutes with the top off (so a total of 50 minutes). My problem is that at 45 minutes the bottom is starting to burn. I know this book calls for medium dark bread, but at 50 minutes the bread would be on fire. I've tested my oven with a thermometer and it is the correct temperature. If I take the bread out earlier, it isn't done in the middle. The crumb is wet. I've raised the dutch oven as high as I can from the bottom of the oven. I start with a preheated dutch oven. My question, is what temperature do you cook your bread at?